Why Won't My Egg Whites Whip?

Q: I ruined two batches of egg whites trying to make an almond sponge cake. I watched the eggs the whole time and they seemed to go from frothy to over whipped without ever reaching the soft or stiff peak stages. I started them off in medium (6) speed on my stand mixer and increased to eight. I made sure to clean my bowl and whisk. Do you have any idea what I did wrong?

Sent by Vanessa

Editor: I'm really scratching my head over this one. Readers, do you have any theories?